Exhaust / Fuelling Question

When I fitted the 4 into 1 to the Zephyr I noticed that the headers, whilst
second hand, were quite shiny and silver.

They are now a bit bronzy looking, and I have observed that the oil
temperature is a smidge hotter after a run than it used to be.

The new exhaust is much thinner gauge steel than the old OEM chromed jobbie,
so I put it down to this, as performance seems okay.

When I had the zorst off yesterday I noticed that the valves (where visible
through the ports) were a bit white.

Is this something I should be worried about?
Do the carbs need rejetting?
Is rejetting a DIY job, or is it a black art requiring the services of the
grand wizard of carburation (AKA Lozzo)?

TIA

--
Dan L (Oldbloke)
My bike 1996 Kawasaki ZR1100 Zephyr
M'boy's bike 2003 Honda NSR125R (Going)
Spare Bike 1990 Suzuki TS50X (Patio Ornament)
BOTAFOT #140 (KotL 2005), X-FOT#000, DIAABTCOD #26, BOMB#18 (slow)

 

Dan L scribbled on the back of a napkin:

That all sounds like it's running a bit leaner than it has before.

Probably - only way to really find out is to stick a probe up its arse,
sorry, exhaust and run it, preferably on a rolling road so you can
figure out if it's running a bit too lean.

With plenty of plug chops you can probably do it yourself or with some
help from any of the esteemed members of this group.

 

I am really embarrassed to admit this, but I have heard the term "plug chop"
many times, and nodded as if I know WTF it means, but actually I don't.

Could you enlighten me please (and don't tell anyone else I asked you).

--
Dan L (Oldbloke)
My bike 1996 Kawasaki ZR1100 Zephyr
M'boy's bike 2003 Honda NSR125R (Going)
Spare Bike 1990 Suzuki TS50X (Patio Ornament)
BOTAFOT #140 (KotL 2005), X-FOT#000, DIAABTCOD #26, BOMB#18 (slow)

 

Find a nice, clear bit of road and welly it at full/whatever throttle for a
bit. Then, before you let off the throttle hit the kill switch, pull the
clutch and coast to a stop. Then, whip out your plugs and check them. The
colour of the plug will give an indication of the mixture at that amount of
throttle.

 

Dan L scribbled on the back of a napkin:

The simple version - you ride the bike and keep the revs up to the revs
that you want to check the fuelling for (which you'd normally do at
several points spread across the rev range so you can check if the
fuelling is OK across the whole range) for a couple of minutes so the
mixture can settle in properly, then hit the kill switch and coast to a
halt. Easier if you also pull in the clutch...

You then pull the spark plugs and check the colour of the deposit on
the plug, which will tell you if it's running too lean or too rich. Or
right, obviously.

Nah, I'm sure that between myself and the rest of UKRM we can keep it a
secret.

Yeah, right.

 

Cheers Timo (and LozH).

So, assuming it needs rejetting, is this a scientific thing or trial and
error, because getting the carbs off is a right PITA.

--
Dan L (Oldbloke)
My bike 1996 Kawasaki ZR1100 Zephyr
M'boy's bike 2003 Honda NSR125R (Going)
Spare Bike 1990 Suzuki TS50X (Patio Ornament)
BOTAFOT #140 (KotL 2005), X-FOT#000, DIAABTCOD #26, BOMB#18 (slow)

 

Dan L scribbled on the back of a napkin:

I'll be a right PITA because you'll end up trying several jet sizes
until you get the right one. It'll be the same if you go on a rolling
road or not in that case as it's mostly a case of change/adjust
jets/needles, run bike, do it again etc pp ad nauseam.

 

Is it easy to get the tops off the carbs at all? (Assuming these are the
same as others. I know ***** all* about Zephyrs...) If so, try raising the
needle up a notch or so (again, assuming these carbs have needles with clips
and notches in...). This will richen things up a touch in mid-throttle and
may help a bit for now.

As for doing it properly, getting it *perfect* is a right pain in the arse,
but you may well be able to get it right enough to be better and safe by
fiddling with the needles and increasing the size of the main jets a bit.

A world of fiddling, and pissing the neighbours off by screwing up and down
the road awaits you. Have fun! )

 

Fuckit then, I'll have to get the remains of the stock system over to that
nice Mr Pip soonest to see whether he can stitch the rusty bits back to the
rustier bits. The 4 into 1 was always only going to be a temprary fix as it
makes the bike look unbalanced, and means I have no centrestand.

--
Dan L (Oldbloke)
My bike 1996 Kawasaki ZR1100 Zephyr
M'boy's bike 2003 Honda NSR125R (Going)
Spare Bike 1990 Suzuki TS50X (Patio Ornament)
BOTAFOT #140 (KotL 2005), X-FOT#000, DIAABTCOD #26, BOMB#18 (slow)

 

Heh, google for info about my neighbours, they're fucking cunts of the worst
water, so this sounds like a plan.

The zephyr carbs have shiny tops that look like pan lids which shouldn't be
too difficult to get off. I believe there are diaphragms under them. I are
mostly a numpty with complicated carbs, my main experience is with the
little Mikuni VM unit off the TS50 which I have happily stripped and
rebuilt. The zephyr carbs appear to be a slightly different animal.

--
Dan L (Oldbloke)
My bike 1996 Kawasaki ZR1100 Zephyr
M'boy's bike 2003 Honda NSR125R (Going)
Spare Bike 1990 Suzuki TS50X (Patio Ornament)
BOTAFOT #140 (KotL 2005), X-FOT#000, DIAABTCOD #26, BOMB#18 (slow)

 

Andy Bonwick scribbled on the back of a napkin:

And why do you think I mentioned the "rolling road" bit above, hmm?

 

Andy Bonwick wrote:

i'm reliably informed that road and track in Aylesbury are a set of
jolly decent fellows, with the added bonus that tehy know what they're
doing.

--
Dnc
<this space pending>
B1200 - Back ~|~ VS800 - borked
TS150 - squatting ~|~ V2300 - flat cap and rug

MIB#26 two#54(soiled) UKRMMA#26 BOTAFOT#153 X-FOT#003

 

Plug chops are free.

 

Road and Track, which are conveniently near to Oldbloke, will do him a
dynorun for a tenner - then, if he needs anything doing, it'll end up
costing him about 30 quid iirc[1].

http://www.roadandtrack.co.uk/ (no affiliation, just heard good things)

[1] they've done quite a lot of work for the local NCC county - as you
can imagine, their machines generally need this kind of setup,
mismatched engine/exhausts/etc



--
Dnc
<this space pending>
B1200 - Back ~|~ VS800 - borked
TS150 - squatting ~|~ V2300 - flat cap and rug

MIB#26 two#54(soiled) UKRMMA#26 BOTAFOT#153 X-FOT#003

 

Not to mention the fact that it might not be a jet problem, and they'd
know this and be able to advise/fix as necessary - rather than shelling
out time and effort on plug chopping to not solve the problem.

--
Dnc
<this space pending>
B1200 - Back ~|~ VS800 - borked
TS150 - squatting ~|~ V2300 - flat cap and rug

MIB#26 two#54(soiled) UKRMMA#26 BOTAFOT#153 X-FOT#003

 

A permanent monitor is useful if you don't mind a bit of drilling and
welding:
http://www.knfilters.com/airfuelmonitors.htm

 

Andy Bonwick scribbled on the back of a napkin:

Welcome to the club.

 

There is that.

I have a tin of Guzzi ones - **** knows where I got them - and the jets
themselves can be easily changed at the side of the road.

I did have a problem with jetting when I put the new 'Conti' exhausts in
place of the old Dunstalls but after two changes I got it as right as it
was going to be by chopping. In fact it was a lot better than before; I
lost some of the bogging down effect caused by the oversize carbs at low
revs and the top over rich fuelling.

As a quick and dirty way of seeing if fuelling is a problem plug chops
are useful and cheap but to do it, as you say, right with proof then a
dyno is really the only option.

 

FWIW the latest edition of one of the monthly bike comics has an
article about Taking Your Bike To A Rolling Road. I can't lay my
hands on it ATM, but I'm 90% sure it was in RIDE.

--
<8P Wizard
Suzuki GS550 "I like that. Nicely shite" - TOG
BMW 520i (to make Oldbloke jealous)
ANORAK#17b BOMB#19 BOTAFOT#138 BREast#5 COFF#24
COSOC#8 DFV#11 STG#1
Remove location from email address to reply

 

Actually yes.

This fuelling lark appears to be a fine / black art.


--
Dan L (Oldbloke)
My bike 1996 Kawasaki ZR1100 Zephyr
M'boy's bike 2003 Honda NSR125R (Going)
Spare Bike 1990 Suzuki TS50X (Patio Ornament)
BOTAFOT #140 (KotL 2005), X-FOT#000, DIAABTCOD #26, BOMB#18 (slow)